We are ALL biased in one way or another
To me, it is like comparing apples and oranges. Both systems had some killer games, exclusives, strengths, and weaknesses. I too owned and still own the "16 bit wars" systems(including the TG-16), and there are arguments for all three being the best.
I can say with complete honesty that although I am both a huge Sega and Nintendo fan, the SNES has held up quite well, as is quickly becomming one of my favorite top five video game systems to PLAY. I love both systems equally and feel that both were neck and neck back in the day for totally different reasons. Either system has a great library of over 700 games that would keep anyone busy.
Now, back to the question at hand. There was a window of time there that the Genesis was the best selling video game system in the US. To me it was an edgier system, one that catered to more an adult audience, as well as having some amazing arcade and sports titles for the time. The Phantasy Star Series and Shining Force Series also was played very heavily with me and my friends. Rennovation labled games also were in high demant at my house(Gain Ground, El Viento, Master of Monsters) With that being said, some of its strengths were also its weaknesses. Becasue it was an amazing system for sports titles, everyone and their mom was making sports titles for it. Also, every company seemed to be trying to duplicate the success of Sonic, so there also was a ridcioulous amount of average platform mascots on the system as well. I have my Sega CD/32X combo hooked up, with a Genesis 6-pak cart in it at all times. Golden Axe is the most played game at my house.
What the Snes lacked in processor speed it made up with color and overall more polished quality to many first party titles. Titles like Super Mario World, Zelda, Metroid, among other great exclusives were very well done, holding up today in terms of varied gameplay, length, and replay value. The Snes is the system that I see my wife always asking about, and one that I would play more when I am in family settings.
I will not prove you wrong becasue in some ways you are right. The Genesis was not equal to the Snes, in some ways it was flat out better(processing speed, arcade style gameplay), and in other ways it was much worse(graphics, and the dreaded god awful sound)
While the Genesis did have a "window of time" in which it was on top, I feel that honestly the Snes has aged more graceully...but I still play my Sega and consider them both on par for different reasons.